When you can't seem to keep the chain adjusted...you are there. The front sprocket takes the beating. The teeth wave.
Jack your bike up and rotate the rear wheel until you get the chain the tightest. Lower the bike and adjust your chain. If you can't figure out what I am mean by "until you get the chain the tightest", your chain is fine.
Chain life 20K miles is average with about 5K more if you don't mind a loose chain and 15K more if you are like well never mind.
How many miles you put on your sickle in a year needs to be factored into your question, "Am I close" If you put 5 grand on her in a year you are one year away. If you put 5 grand on her in three months you need to order a chain kit now.
